基于MMF理论的平纹织物复合材料细观强度性能研究

Research on Microscale Strengths for Plain-Woven Fabric Composites Based on MMF Theory

为探究平纹织物复合材料的组分细观强度,笔者基于细观力学失效(micro-mechanics of failure, MMF)理论提出了一种确定平纹织物复合材料细观强度的跨尺度分析方法。建立了单向带复合材料和平纹织物复合材料纤维束的细观尺度代表体积单元有限元模型,并介绍了基于代表体积单元模型的宏-细观应力转换方法;根据单向带复合材料的宏观强度测试结果确定了单向带复合材料的组分细观强度;以单向带复合材料组分细观强度为基础,根据组分强度不变的假设反推了平纹织物复合材料的纤维束强度,并以平纹织物复合材料层板宏观强度试验结果对反推所得的纤维束强度进行了校验与修正;以纤维束强度为基础,结合细观尺度代表体积单元模型,确定了平纹织物复合材料的纤维、基体组分强度。针对T300/环氧复合材料,应用上述方法并结合宏观强度测试,确定了平纹织物复合材料的组分细观强度。研究结果表明所提出的分析方法和计算结果与实验结果较为符合,可应用于实际工程复合材料。

In order to investigate the constituents′microscale strengths of the plain-woven fabric composites,the multi-scale method was proposed to determine the microscale strength of plain woven fabric composites baseed on micromechanics of failure.The finite element model of microscale representative unit cell(RUC)of the unidirectional composites and fiber buddles of the plain-woven fabric composites was established,and macro-meso stress transformation method was introduced based on the RUC.The microscale strengths of the constituents in the unidirectional composites were achieved based on the tested macroscale strengths.Under the microscale strength invariance hypothesis,the strengths of the fiber buddles from the plain-woven fabric composites were back-calculated based on the microscale strength of the unidirectional composites,and the strengths of the fiber buddles from backward calculation were verified and corrected based on the tested strengths of the plain-woven fabric laminates.With the microscale RUC model and strengths of the fiber buddles,the microscale strengths of the constituents suitable for fiber and matrix components of the plain-woven fabric composites were determined.For the T300/Epoxy composite,the above methods have been applied to determine the microscale strengths of the constituents of plain-woven fabric.The results show that the proposed analysis method and calculation results are in good agreement with the experimental results and can be applied to the practical engineering composite materials.